Method of and tool for shaping and ironing sheet metal



June 27, 1939. F, p; STULL 2,163,715

METHOD OF AND TOOL FOR SHAPING AND IRONING SHEET METAL Filed Sept. 14, 1935 2 Sheets-Sheet l 28a I I H 2a f1}! 27/ I 1 29a 5 32a '9 /0 gwtnnto'o F4 75 7 577/11 June 27, 193 9. I STULL 2,163,715

METHOD OF AND TOOL FOR SHAPING AND IRONING SHEET METAL Filed Sept. 14, 1933 2 Sheets-Sheet 2 FA V5 7 $7011 dmm s 21) pressure; to provide a. device of this class which Figs. 6a and 6b are diagrammatic illustrations 20 Patented June 27, 19 39 UNITED STATES PATENT OFFICE METHOD OF AND TOOL FOR SHAPING AND IRONING SHEET METAL 1 Faye P. Stull, Youngstown, Ohio Application September 14, 1933, Serial No. 689,436

25 Claims. (01. 153-32) This invention relates to'a method of and a shrinking the damaged or dented area or a pordevice or tool for ironing or smoothing and shaption thereof without employing heat in the ing sheet metal, and while not limited thereto, it stretching and shrinking process. is particularly adapted for ironing out damaged In the drawings:

fenders of motor and analogous vehicles, the Figure 1 is a view in side elevation of a sheet 5 primary object being to provide a method of metal ironer or shaper constructed in accordance ironing or smoothing sheet metal which results with the features of the present invention; in work of a superior character and to produce a Fig. 2 is a transverse vertical section taken tool or apparatus for carrying out the method substantially on the line 2-2, Fig. 1, particuwhich is highly efficient, easily handled and is of larly showing the air or fluid actuated hammer 10 generally improved construction throughout. assembly and coacting parts; I

More specific objects are: to provide a power Fig. 3 is a detail view in elevation and partly device or tool for ironing or smoothing sheet in section of a piston comprising part of the metal, more particularly automobile fenders and assembly of Fig. 1;

like parts, of the hammer type embodying a self- Fig. 4 is a view also in elevation and section of 15 contained fluid-actuated power unit which is a cylinder also comprising part of said assembly; under convenient and accurate control at all Figs. 5, 6 and 7 are detail views of different times and which is constructed to deliver maxitypes of dies adapted for use with the hammer mum power with a relatively low supply of fluid assembly; and

has a true ironing action and with ample power of how the die shown in Fig. 6 may be employed in at hand to do the most difficult work without the preliminary straightening operation of sheet damage to the metal being operated upon and metal part which would ordinarily require stretchwithout tiring the operator; to provide a device ing and shrinking of the metal; and Fig. 6c shows of this class which embodies an air or like fiuidthe metal after being finally ironed or smoothed 25 actuated hammer and coacting die assembly toby the die shown in Figs. 1 and 5. gether with a frame construction for the as- Referring to the drawings in detail, the frame sembly which cooperate to produce work of a of the device is generally indicated at 5 and is superior type with marked flexibility and ease of formed with an inset portion 5a, the latter servoperation; to provide a fender ironer which is ing to avoid the tire of a motor or analogous 30 light in weight, simple in construction and vehicle when used for fender ironing purposes. economical to manufacture yet strong and The f ame iS pre e y o generally U durable, and which embodies'working parts which shaped contour and is rigid or substantially nonmay be easily and quickly removed and replaced yielding p po Which Will Subsequently be in accordance with the character of the work permade apparent, and as here shown is of forged 35 formed and for renewal or repair, I beam construction with a tubular or hollow die A feature of this invention resides in an arholding portion or leg 5b and a clamp head 6, rangement for holding both dies in contact with which may be welded or otherwise secured to the the fender on opposite sides thereof during the main handle portion or may be made integral with 40 time that the dies are being moved over the surthe latter. In certain instances I have made the 40 face while a rapid succession of blows is imparted frame of tubular or pipe construction throughout to one of the dies. This result is accomplished, with good results. Removably seated in the diewithout necessitating a split or pivoted yoke, by holding portion 5b is a die I, which in Fig. l is making one of the dies movable, together with shown with asubstantially round head having a 5 the associated hammer assembly, relative to a v metal-contacting surface of a radius such as rigid yoke. will facilitate manipulation of the tool but which Generally stated, the method consists in placmay be given any desired or approved shape, such ing opposed'dies against opposed surfaces of the for example as that shown at la in Fig. 6 or at sheet metal to be operated uponand then movlb in Fig. 7, depending upon the character of i g thedies over said surfaces and continuously in the work involved. The die I is comparable to cgntact therewith while delivering a succession of the conventional anvil die, since it is held against impact blows to at least one of said dies. the under side of the fender, or against the side The invention is also concerned with a parof the sheet opposite to that acted upon by the ticularly advantageous method of ironing or upper or hammer die, to be described. smoothing sheet metal by in effect stretching and The hammer assembly and coacting parts com- 55 prise a housing 8 which may be either formed integrally with or suitably secured to the one end of a main handle member 9, the latter preferably being knurled and of hollow or tubular construction and is provided at its opposite end with an internally threaded nipple portion adapted to receive a nipple H), for connecting the tool to a source of air or like fluid pressure.

To facilitate accurate positioning of the housing 8, and consequently the parts carried by said housing, with respect to the die 1, the handle 9 is provided with a centering and stop lug ll adapted to engage in a keyway or recess Ha formed in the side of the head 6.

The hammer assembly comprises a cylinder I2 formed at its lower extremity with an annular interior groove l3 communicating with a series of lower air-escapement or relief ports 14 which prevent entrapping of air between a hammer die and a piston hammer to be described, said cylinder being provided at an intermediate point with an annular stop shoulder I above which is a lower piston chamber l5aand an air-inlet port l6, and at its upper extremity the cylinder is provided with an annular valve recess l1 and a series of exhaust ports l8. A hammer piston l9, (note Fig. 3) is provided and has a skirt or hammer portion having a relatively snug sliding fit in the lower extremity of the cylinder [2, and an upper valve portion formed with an annular valve flange 20 having a relatively snug sliding fit in the intermediate portion of the cylinder I2, said flange tapering into a neck portion formed with a series of upwardly directed valve ports 2| which communicate with an upper piston chamber 22.

The inlet port [6 has a graduated inlet in the form of a tapered divergent concavity l6a which is of gradually increasing air-flow capacity (note Fig. 4) and said port is adapted for adjustable registration with a port lGb formed in the end of the handle 9, note particularly Fig. 1. Thus by rotating cylinder l2 by means to be described, the air pressure and resultant power impact exerted by the piston on the upper or hammer die may be regulated.

At its lower extremity the cylinder l2 isformed with an annular key groove in which a resilient or spring key ring 23 is seated, said key releasably engaging in a complemental groove 24 formed in the neck or shank 25a. of an upper or hammer die 25. The hammer die 25 constantly bears on the surface of the metal and is impacted by the hammer portion of piston I9.

The upper extremity of the cylinder 8 is threaded and thereon is mounted a cylinder head or cap 26, and between this cap and the housing 8 a compression spring 21 is inserted. Projecting outwardly from the cap 26 is a knurled thumb piece or handle 28, to facilitate rotation of the cylinder l2 for air adjustment purposes as will be more fully explained in the operation of the device or tool. The cap may be secured against displacement by screws 2811.

A control handle 29 for moving the hammer assembly into working position and also for regulating the working approach of the hammer to the die, or the working pressure of the hammer with respect to the metal being operated upon, is provided and has a yoke portion 29a which is pivoted to the housing 8, and pivotally connected to said yoke is a yoke bracket 30 having a boss 3! at the top thereof adapted to engage in a depression or recess-formed in the top of the cap 26. By depressing the handle 29, the cylinder l2 together with the assembly carried thereby including the hammer 25 is moved down into working position, a certain range of working control being permitted between the main carrying handle 9 and the handle 29, the tool preferably being held so that the handle 29 bears against the palm of the hand in the region of the thumb with the lever 28 within easy reaching distance of the thumb and forefinger during the actual working operation.

Associated with the port or passage I6b is an air-inlet valve 32 provided with an upwardlyprojecting adjustable spring-pressed ,stem 32a adapted to be depressed by the handle 29. This valve 32 may be used in conjunction with, or in place of the inlet valve or port 16, the stem 32a. being adjustable so that the handle-.29 will contact therewith and open the valveapproximately at the time the hammer die 25 contacts the metal. The adjustment may be such that the power delivered may be gradually increased as the dies approach more nearly to one another, or directly in proportion to the pressure of the dies on the metal. It will also be noted that this valve will efiectively seal the power unit against leakage when not in use should the line valve be turned on.

A general statement of the operation of the tool tog-ether with an enumeration of some of its advantages follows:

Let it be assumed by way of example that the sheet metal part to be operated upon is the damaged fender of an automobile.

If the fender 'is badly bent or thrown out of shape, it can be rough-shaped or straightened by means of a hammer or other convenient tool or method. In doing this, no extra precaution need be taken to prevent denting of the fender. The shaper or ironer, having been connected with a suitable source or supply of air under pressure, is then moved into position with the fender in the nose opening between the die I and hammer die 25. The upper hammer die 25 and the lower die I are held in constant contact with the work while the piston l9 impacts the hammer die, the tool being moved in any desired direction with the dies bearing against opposed surfaces of the metal. The pressure of the dies on the metal need be relatively light, if any, it simply being necessary that they contact said surfaces. This results in a true ironing action. For ordinary purposes, the type of die shown in Figs. 1, 2 and 5 is suitable. The operator depresses the handle 29, thereby depressing the cylinder l2 together with the parts carried thereby until the port 16 partly or wholly registers with the port 16b, and/or until the handle contacts valve stem 32a and opens valve 32. Air under pressure then passes through the ports lBb and I6 into lower piston chamber 150., and is directed against the flange 20, exerting suflicient pressure on the piston 19 to move the latter upwardly until the flange 20 reaches the annular recess I1, whereupon air passes through valve ports 2| into upper piston chamber 22, cushioning the upward stroke of the piston and then driving the piston downwardly." .When the upper wall of the piston passes and uncovers the ports l8 on its downward movement, the air escapes from the said ports, relieving the chamber 22 of pressure preparatory to the return or back stroke of the piston. The resultant rapid reciprocatory or hammer action is well understood by those having a knowledge of air "and like fluid-actuated hammers, drills and analogous tools.

It will be noted that there are no sharp or abrupt turns or angles to hinder free flow of the air and create turbulence, the air flowing or pass ing uniformly into lower piston chamber l5, pushing piston up until recess I1 is reached by flange 20, whereupon the air passes into upper piston chamber 22 and the differential pressure drives the piston downwardly. Thus maximum efliciency is obtained. Actual experience shows that approximately 2580 strokes per minute may be obtained with a pressure of approximately fifty pounds, so that the pressure available at most small garages or repair shops is suflicient.

The main handle 9, hammer-control lever 28 and handle 29 are so relatively located and arranged that only one hand is required in operating the tool. Thus the lever 28 may be gripped between the forefinger andthumb when it is desired to adjust the air pressure and consequently the impact blows on the hammer die 25, while the handle 29 may be depressed by the thumb portion of the palm more closely against the handle 9 to increase the pressure of the hammer die onthe metal as the latter becomes smoother.

Due to the fact that the die and hammer are supported by a rigid frame, they are always held in aligned position with respect to one another and the metal therebetween with the lower die in non-yielding relation to the upper die, a feature which I have found adds materially to the effectiveness of the work performed by the tool. Another feature is the interchangeability of the power unit, including the main handle 9, with respect to varying types and shapes of frames.

The dies are preferably fitted intothe tubular. socket 5b with a relatively snug yet freely slidable' fit so that they may be easily removed and replaced when desired. The diesla and 11) shown in Figs. 6 and 7 illustrate how different types of dies may be used for different types of work. The hammer 25 may also be easily removed and replaced'simply by striking it with the piston I9 when in a raised position or by turning on the air when the lower die is removed. The cylinder l2 and the assembly carried thereby may be removed simply by removing the hammer, then moving the cap 26 clear of the boss 3| and swinging back the yoke bracket 30.

By the use of air as the operating medium together with the convenient controls, a smooth steady flow of power is always available and regulable to meet varying conditions of work. The pressure of the upper and lower dies on the metal may be governed by the operator at all times by the lever 29. Thus during the initial shaping operation, the dies accommodate the irregularities of the metal and as the latter become smoother, the dies adjust themselves closer together, gradually yet quickly smoothing out the metal with accurate convenient adjustment of working power and pressure available to meet working conditions.,., The--metal may be stretched, or stretching may be prevented ..-a't-the will of the operator by adjusting the force of impact of the piston. In actual practice I have found that a sheet metal part such as an automobile fender can be ironed out without seriously impairing the finish, provided proper care is exercised in controlling the working pressure of the dies and the air pressure. In actual practice, I prefer to just keep the dies against the work and let the tool follow the contour of the metal, not holding the tool rigid but allowing it to move over the surface freely.

In Figs. 6a, 6b and Go, I illustrate a method of ironing out a damaged fender or analogous sheet metal part in which the metal has become stretched and which has heretofore been ironed or smoothed by heating and shrinking certain portions of the damaged area. In carrying out this method, I preferably use dies of the contour shown in Fig. 6, the said dies having coacting male and female portions 33 and 34, keys 35 and 35a being provided to hold the dies against angular displacement in the die, sockets. In Fig. 6a, Ishow a piece of sheet metal 36 having a damaged portion 31 in which the metal-has been so badly distorted or stretched as to ordinarily require alternate stretching and shrinking to put it back into shape. I have devised a method of ironing such damaged metal rapidly, easily and efficiently by first drawing the metal into a series of humps or ridges 38 with the dies shown in Fig. 6 and then employing the dies 1 and 25 to iron out these humps or ridges, the metal in effect being expanded into the adjacent area and upon completion having a smooth regular contour as at 36a, Fig. 60.

It will be understood that the foregoing moreor less specific description is by way of explanation only and is not to be construed as a limitation, and that various minor changes in structure and assembly may be adopted within the scope of the appended claims.

I claim:

1. A power tool assembly for ironing and shaping sheet metal comprising an anvil die to be held against one side of thesheet to be operated upon and a self-contained portable power unit capable of being carried in the hand of an operator and including a hammer die to'be held against thevother side of the sheet in opposed relation to the anvil die and a cylinder having a fluid-actuated power piston mounted to reciprocate therein and means associated with its lower extremity for removably holding the hammer die in a position to be impacted by the piston while it is held against the sheet and moved thereover.

2. A power toolfor ironing and shaping sheet metal comprising a rigid frame of generally U- shaped contour having a hollow die-holding por-' tion at one extremity and a clamp at its opposite extremity, a die in said hollow portion, a handle member fixed at one extremity in said clamp and having a housing at its opposite extremity, and 50 a fluid-actuated hammer assembly carried by said housing and including a hammer die in aligned relation with said die.

3. A portable power tool for ironing and shaping sheet metal comprising a frame, upper and lower dies carried by said frame in spaced aligned relation, a manually controlled hand lever for moving the upper die against the surface of the metal being operated upon, and a self-contained fluid-actuated power unit for delivering .a succession of impact blows to said upper die, said frame being provided with a handle for moving the dies over the surface of the work.

A power tool for ironing and shaping sheet metal comprising a rigid frame, upper and lower 5. A power tool for ironing and shaping sheet metal comprising a frame, a lower die carried by said frame at one extremity thereof, a main carrying handle secured to the opposite extremity of said frame, a housing at the forward extremity of said handle, a fluid-actuated power assembly movably mounted in said housing, an upper die associated with said assembly, a spring for normally urging said assembly and die toward retracted position, and a manually controlled lever for moving said assembly and upper die into working position against the resistance of said spring with the die against the surface of the metal being operated upon.

6. A power tool for ironing and shaping sheet metal comprising a rigid frame of generally U- shaped contour having a hollow die-holding portion at one extremity and fastening means at its opposite extremity, a lower die in said holding portion, a hollow handle member fixed at one extremity in said fastening means and having a housing at its opposite extremity, a cylinder slidably mounted in said housing, a fluid-actuated hammer assembly mounted in said cylinder and including an upper hammer die in aligned relation with said lower die, and means for admitting a fluid medium through said handle and cylinder to said assembly to impart a succession of blows to said hammer die.

'7. A power tool for ironing and shaping sheet metal comprising a rigid frame of generally U- shaped contour having a hollow die-holding portion at one extremity and a clamp at its opposite extremity, a lower die in said hollow portion, a hollow handle member fixed at one extremity in said clamp and having a housing at its opposite extremity, a cylinder slidably and rotatably mounted in said housing, inlet ports for communicating the hollow handle with the interior of the cylinder, a fluid-actuated hammer assembly mounted in said cylinder and including a hammer die in aligned relation with said lower die, means for admitting fluid medium through said ports to said assembly to impart a succession of blows to said hammer die, and means for rotating said cylinder to adjust the volume of fluid passing through said inlet ports.

extremity and fastening means at its opposite extremity, a lower die in said holder, a hollow handle member fixed at one extremity in said fastening means and having a housing at its opposite extremity, a cylinder slidably and rotatably mounted in said housing, inlet ports for communicating the hollow handle with the interior of the cylinder, a fluid-actuated hammer assembly mounted in said cylinder and including a hammer die in aligned relation with said lower die, means for admitting a fluid medium into said handle and a hand-controlled lever for depressing said cylinder to bring said ports into registration and admit the fluid medium to said assembly and simultaneously move the hammer die against the metal being operated upon.

9. A power tool for ironing and shaping sheet metal comprising a rigid frame of generally U- shaped contour having a hollow die-holding leg at one extremity and a clamp at its opposite extremity, a lower die in said leg, a hollow main carrying handle fixed at one extremity in said clamp and having a housing at its opposite extremity, a cylinder slidably mounted in said housing, inlet ports for communicating the hollow handle with the interior of the cylinder, a

fluid-actuated hammer assembly mounted in said cylinder and including a hammer die in the lower extremity of the cylinder in aligned relation with said lower die, a piston mounted to reciprocate in the cylinder above the hammer die, said cylinder being provided with exhaust ports at its upper extremity, a spring for normally urging the cylinder together with the parts carried thereby toward retracted position with the inlet port thereof out of registration with the inlet port of the handle, and a hand-controlled lever for depressing the cylinder together with the piston and hammer die into working position.

10. A portable power tool forironing andshaping sheet metal comprising a rigid frame, a lower die removably mounted in one extremity of said frame, a self-contained fluid-actuated power unit mounted at the opposite extremity of said frame and embodying a cylinder, a reciprocating hammer piston mounted in said cylinder and a hammer die removably keyed in the lower extremity of the cylinder and adapted to be impacted by said piston and manually controlled means for adjusting the working position of said unit with respect to the lower die.

11. A portable power tool for ironing and shaping sheet metal comprising a rigid main frame having a lower die at one end thereof and a holder at its opposite end, a handle adapted to be removably fitted into said holder at its one extremity and carrying a power unit at its opposite extremity, an upper die associated with said unit, and means for angularly positioning said handle in said holder to ensure accurate alignment of said dies.

12. The method of ironing and shaping sheet metal which consists in moving a pair of opposed dies over the opposed surfaces of the metal to be operated upon while holding one of the dies in non-yielding relation to the other die with both dies in constant contact with opposed surfaces of the metal and delivering a series of impact blows to at least one of said dies.

13. The method of ironing and shaping sheet metal which consists in placing a pair of dies in opposed relation against opposed surfaces of the metal to be operated upon, moving the dies over said surfaces and continuously in contact therewith while delivering a series of impact blows to at least one of said dies, one of said dies being supported in rigid non-yielding association with respect to the other die.

14. A portable power tool for ironing and shaping sheet metal comprising a frame, upper and lower dies carried in spaced opposed relation by said frame, manually-controlled means for adjusting the upper die towards the lower die to bring both dies against opposed surfaces of the metal to be operated upon, and a reciprocating power piston adapted to deliver a succession of impact blows to the upper die while the latter is held under manually-controlled pressure against the surface of the metal and is being moved thereover.

15. A portable power tool for ironing and shaping sheet metal comprising a substantially rigid frame of generally C-shaped contour, upper and lower dies carried in spaced opposed relation by said frame, a depressible supporting means for said upper die, a manually-controlled lever for depressing said supporting means to thereby adjust the upper die towards the lower die, a reciprocating power piston operatively mounted over said upper die for delivering a succession of impact blows thereto while the said upper die is being pressed against the metal by said lever and moved over the surface thereof, and a main carrying handle, saidlever being mounted for hand control adjacent said handle.

16. A portable power tool for ironing and shaping sheet metal comprising a. rigid frame of substantally C-shaped contour having a nose opening at one extremity thereof, opposed upper and lower dies mounted in said frame adjacent said opening, a depressible supporting means for said upper die, a manually controlled lever for depressing said supporting means to bring said upper die against the surface of the metal to be operated upon and adjust the Working pressure thereof while the dies are being moved over the surface of the metal, a reciprocating power piston operatively mounted above said upper die in said supporting means for delivering a succession of, impact blows thereto, and a main carrying handle for the tool, said lever being so arranged with. respect to said handle as to be under the control of the hand of the operator which grasps. said handle.

17. A power tool for ironing and shaping sheet metal comprising a substantially C-shaped frame having a nose opening in one extremity thereof, upper and lower dies mounted adjacent said opening, a depressible supporting means for said upper die, a fluid actuated piston assembly operatively mounted in said supporting means above said upper die for delivering a series of impact blows thereto, a manually-controlled lever for depressing said supporting means to adjust said upper die toward said lower die, a main carrying handle provided with an inlet port for the piston assembly, a valve for controlling the admission of a fluid medium through said port, said valve being so arranged with respect to said. lever as to be controlled by the operation of the latter.

18. A power tool for ironing and shaping sheet metal comprising a rigid substantially c-shaped frame having a nose opening at one extremity thereof, upper and lower dies mounted in opposed aligned relation adjacent said opening, a fluid actuated power assembly including a cylinder, said upper die being detachably mounted in the lower extremity of said cylinder, a reciprocating hammer piston also mounted in said cylinder above said upper die, a housing for said cylinder, a spring for normally urging said cylinder together with the upper die and piston towards retracted position, and a manually controlled lever pivotally connected to said housing for adjusting said cylinder and the parts carried thereby towards the lower die whereby said dies may be maintained under manually controlled pressure against the surface of the metal being operated upon while the piston is delivering a succession of impact blows to the upper die.

l9. The method of ironing and shaping sheet metal which consists in disposing a pair of dies in opposed relation against opposed surfaces of the metal to be operated upon, maintaining the dies continuously in contact with the said surfaces and under manually-controlled pressure while moving the dies over said surfaces and delivering a series of impact blows to at least one of said dies.

20. The method of ironing and shaping sheet metal which consists in placing upper and lower dies in opposed relation against opposed surfaces with while delivering a series of impact blows to the upper die, and maintaining theupperdie under manually controlled pressure during the ironing operation.

2 2. The method of ironing and smoothing distorted and stretched areas of sheet metal which consists in first drawing the metal in the distorted area into one or more gathers and then subjecting the gathers to the action of opposed dies to iron out the gathers and work the gathered metal into the adjacent area.'

23. A power tool for ironing and shaping sheet metal comprising a yoke having an anvil die at one end and a housing at the other, the housing, anvil die and yoke all being rigid with each other,

a fluid actuated hammer assembly movably mounted in said housing and carrying therewith a hammer die adapted to be alined with the anvil die, said dies having complementary smooth, substantially flat surfaces adapted to engage opposite sides of the sheet metal, the engaging surfaces on the dies being uniformly spaced apart near the central portion thereof whereby to conform to the shape of a smooth section of sheet metal having uniform thickness, handle portions on said yoke by means of which the dies may be moved over the surface of the metal, means for urging the hammer assembly and die toward the anvil die to maintain the dies in engagement with the opposite sides of the metal while the tool is being moved, and means in said hammer assem-' bly for imparting a rapid succession of blows to the hammer die while the dies are being moved over the surface of the metal and in contact therewith.

24. A power tool for ironing and shaping sheet metal comprising a frame, a lower die carried by said frame at one extremity thereof, said frame providing a handle and a housing disposed at the other extremity of the frame in alignment with the lower die, a fluid-actuated power assembly movably mounted in said housing, an upper die associated with said assembly, a spring for normally urging said assembly and die toward retracted position, and a manually controlled lever for moving said assembly and upper die into 

